83,672 research outputs found
Chiral Kinetic Theory
We derive the non-equilibrium kinetic equation describing the motion of
chiral massless particles in the regime where it can be considered classically.
We show that the Berry monopole which appears at the origin of the momentum
space due to level crossing is responsible for the chiral magnetic and vortical
effects.Comment: 4 page
Long String Scattering in c = 1 String Theory
We study the scattering of long strings in c = 1 string theory, both in the
worldsheet description and in the non-singlet sector of the dual matrix quantum
mechanics. From the worldsheet perspective, the scattering amplitudes of long
strings are obtained from a decoupling limit of open strings amplitudes on FZZT
branes, which we compute by integrating Virasoro conformal blocks along with
structure constants of boundary Liouville theory. In particular, we study the
tree level amplitudes of (1) a long string decaying by emitting a closed
string, and (2) the scattering of a pair of long strings. We show that they are
indeed well defined as limits of open string amplitudes, and that our results
are in striking numerical agreement with computations in the adjoint and
bi-adjoint sectors of the dual matrix model (based on proposals of Maldacena
and solutions due to Fidkowski), thereby providing strong evidence of the
duality.Comment: 42 pages, 18 figure
Correlation-enhanced electron-phonon coupling: Applications of GW and screened hybrid functional to bismuthates, chloronitrides, and other high Tc superconductors
We show that the electron-phonon coupling (EPC) in many materials can be
significantly underestimated by the standard density functional theory (DFT) in
the local density approximation (LDA) due to large non-local correlation
effects. We present a simple yet efficient methodology to evaluate the
realistic EPC going beyond LDA by using more advanced and accurate GW and
screened hybrid functional DFT approaches. The corrections we propose explain
the extraordinarily high superconducting temperatures that are observed in two
distinct classes of compounds-the bismuthates and the transition metal
chloronitrides, thus solving a thirty-year-old puzzle. Our work calls for the
critically reevaluation of the EPC of certain phonon modes in many other
materials such as cuprates and iron-based superconductors. The proposed
methodology can be used to design new correlation-enhanced high temperature
superconductors and other functional materials involving electron-phonon
interaction.Comment: Substantilly extended version of the previous manuscript, 19 pages,
10 figures, accepted for publication in Phys. Rev.
The c=1 String Theory S-Matrix Revisited
We revisit the perturbative S-matrix of c=1 string theory from the worldsheet
perspective. We clarify the origin of the leg pole factors, the non-analyticity
of the string amplitudes, and the validity as well as limitations of earlier
computations based on resonance momenta. We compute the tree level 4-point
amplitude and the genus one 2-point reflection amplitude by numerically
integrating Virasoro conformal blocks with DOZZ structure constants on the
sphere and on the torus, with sufficiently generic complex Liouville momenta,
and find agreement with known answers from the c=1 matrix model.Comment: 32 pages, 7 figures; footnote and references added, typos correcte
Spatiotemporal evolution, mineralogical composition, and transport mechanisms of long-runout landslides in Valles Marineris, Mars
Long-runout landslides with transport distances of >50 km are ubiquitous in Valles Marineris (VM), yet the transport mechanisms remain poorly understood. Four decades of studies reveal significant variation in landslide morphology and emplacement age, but how these variations are related to landslide transport mechanisms is not clear. In this study, we address this question by conducting systematic geological mapping and compositional analysis of VM long-runout landslides using high-resolution Mars Reconnaissance Orbiter imagery and spectral data. Our work shows that: (1) a two-zone morphological division (i.e., an inner zone characterized by rotated blocks and an outer zone expressed by a thin sheet with a nearly flat surface) characterizes all major VM landslides; (2) landslide mobility is broadly dependent on landslide mass; and (3) the maximum width of the outer zone and its transport distance are inversely related to the basal friction that was estimated from the surface slope angle of the outer zone. Our comprehensive Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) compositional analysis indicates that hydrated silicates are common in landslide outer zones and nearby trough-floor deposits. Furthermore, outer zones containing hydrated minerals are sometimes associated with longer runout and increased lateral spreading compared to those without detectable hydrated minerals. Finally, with one exception we find that hydrated minerals are absent in the inner zones of the investigated VM landslides. These results as whole suggest that hydrated minerals may have contributed to the magnitude of lateral spreading and long-distance forward transport of major VM landslides
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